Most Common Weight Loss Surgery May Weaken Bones in Adolescents

Obesity is on the rise in adolescents; nearly one in five people aged 2 to 19 years are obese. One strategy for weight loss is surgery, including sleeve gastrectomy (SG), which is the most popular option for young patients. However, the operation may decrease patients’ bone mineral density (BMD), according to a study that was presented at the Radiological Society of North America annual meeting.

“Childhood obesity is a major public health issue that has increased over the last 10 years,” said lead investigator Miriam A. Bredella, MD, professor of radiology at Harvard Medical School in Boston, Massachusetts, and vice chair of the Department of Radiology at Massachusetts General Hospital in Boston, who discussed the findings. “SG is the most common bariatric surgery procedure performed in children and adults.”

“In adults, bariatric surgery can have long-term effects on bone, leading to higher fracture risk,” she explianed. “We wanted to determine the effects of sleeve gastrectomy performed on adolescents during the crucial years when bone mass is being accrued.”

Dr. Bredella and her colleagues evaluated adolescents with moderate to severe obesity. The mean age was 17.5±2.4 years, and mean body mass index (BMI) was 45±7 kg/m². Some of the cohort underwent SG, while the others were evaluated as nonoperative controls. Patients in the SG cohort were followed pre- and one year postoperatively, while the nonoperative controls were followed for one year.

The patients underwent quantitative computed tomography (QCT) at baseline and one year to evaluate volumetric BMD (vBMD) and single voxel 1H-MRS at 3T (PRESS pulse sequence without water suppression) of the lumbar spine (L1), mid femur, and distal tibia.

The SG group lost significantly more weight compared to the nonoperative controls (36±13 kg vs. 0.2±9 kg; P<0.0001). Per the QCT scan, the SG patients, compared to nonoperative controls, had a significant decrease in vBMD (P=0.046). The operative group had an increase in lumbar marrow adipose tissue (MAT) (P=0.013) but when compared to the control group, the difference was not significant (P=0.3). SG patients, compared to controls, had decreased femur and tibia MAT content (P=0.049 and P=0.006, respectively).

“Adolescents who underwent sleeve gastrectomy had bone loss and an increase in bone marrow fat, despite marked loss of body fat,” said Dr. Bredella. “While weight-loss surgery is successful for weight loss and improving metabolic disorders, it has negative effects on bone.”

“We need to identify mechanisms that will help prevent bone loss in these patients and to make adolescents with obesity more aware of bone health,” she added. “Adolescence is the critical time for bone mass accrual, and any process that interferes with bone accrual during this time can have dire consequences later in life.”